Through tip for catheter

ABSTRACT

Catheter having an elongate tubular shaft including an inflation lumen and a guidewire lumen defined therein, the guidewire lumen extending along at least a distal length of an inner tubular member of the elongate tubular shaft. The catheter includes a distal tip member having a proximal end and a distal end, wherein the distal tip member is monolithic and the proximal end of the distal tip member is secured to a distal end of the inner tubular member. The catheter includes a balloon having a proximal portion and a distal portion, the proximal portion of the balloon sealingly coupled to the distal portion of the elongate tubular shaft. The distal portion of the balloon is sealingly coupled to the distal tip member and the balloon defines an inner chamber in communication with the inflation lumen, wherein the proximal end of the distal tip member is disposed within the inner chamber.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No.13/481,532, filed on May 25, 2012, which claims the benefit of U.S.Provisional Patent Application Ser. No. 61/490,444, entitled “ThroughTip For A Catheter” and filed on May 26, 2011, the entire contents ofboth of which are incorporated herein by reference.

BACKGROUND OF THE DISCLOSED SUBJECT MATTER Field of the DisclosedSubject Matter

The disclosed subject matter herein generally relates to medicaldevices, and particularly to a distal tip configuration forintracorporeal devices for therapeutic or diagnostic uses, such asballoon catheters.

Description of Related Subject Matter

In percutaneous transluminal coronary angioplasty (PTCA) procedures, aguiding catheter is advanced in the vasculature of a patient until thedistal tip of the guiding catheter is seated in a desired coronaryartery. A guidewire is advanced out of the distal end of the guidingcatheter into the coronary artery until the distal end of the guidewirecrosses a lesion to be dilated. A dilatation catheter, having aninflatable balloon on the distal portion thereof, is advanced into thecoronary anatomy over the previously introduced guidewire until theballoon of the dilatation catheter is positioned across the lesion. Oncepositioned, the dilatation balloon is inflated with inflation fluid oneor more times to a predetermined size at a suitable pressure to compressthe stenosis against the arterial wall to open up the vascularpassageway. Generally, the inflated diameter of the balloon isapproximately the same diameter as the native diameter of the body lumenbeing dilated to complete the dilatation but not over expand the arterywall. After the balloon is deflated, blood resumes through the dilatedartery and the dilatation catheter and the guidewire can be removedtherefrom.

In such angioplasty procedures, there may be restenosis of the artery,i.e. reformation of the arterial blockage, which necessitates eitheranother angioplasty procedure, or some other method of repairing orstrengthening the dilated area. To reduce the restenosis rate and tostrengthen the dilated area, physicians may additionally oralternatively implant an intravascular prosthesis inside the artery atthe site of the lesion. Such stents may be bare metal, polymeric, orcoated with a drug or other therapeutic agent. Stents may also be usedto repair vessels having an intimal flap or dissection or to generallystrengthen a weakened section of a vessel. Stents are usually deliveredto a desired location within a coronary artery in a contracted conditionon a balloon of a catheter which is similar in many respects to aballoon angioplasty catheter, and expanded to a larger diameter byexpansion of the balloon. The balloon is deflated to remove the catheterwith the stent implanted within the artery at the site of the dilatedlesion. Coverings on an inner or an outer surface of the stent have beenused in, for example, the treatment of pseudo-aneurysms and perforatedarteries, and to prevent prolapse of plaque. Similarly, vascular graftscomprising cylindrical tubes made from tissue or synthetic materialssuch as polyester, expanded polytetrafluoroethylene, and DACRON may beimplanted in vessels to strengthen or repair the vessel, or used in ananastomosis procedure to connect vessels segments together. For detailsof example stents, see for example, U.S. Pat. No. 5,507,768 (Lau, etal.) and U.S. Pat. No. 5,458,615 (Klemm, et al.), which are incorporatedherein by reference.

In addition to PTA, PTCA, and atherectomy procedures, balloon cathetersare also used to the peripheral system such as in the veins system orthe like. For instance, a balloon catheter is initially advanced over aguidewire to position the balloon adjacent a stenotic lesion. Once inplace, the balloon is then inflated, and the restriction of the vesselis opened. Likewise, balloon catheters are also used for treatment ofother luminal systems throughout the body.

Typically, balloon catheters comprise a hollow catheter shaft with aballoon secured at a distal end. The interior of the balloon is in afluid flow relation with an inflation lumen extending along a length ofthe shaft. Fluid under pressure can thereby be supplied to the interiorof the balloon through the inflation lumen. To position the balloon atthe stenosed region, the catheter shaft is designed to have suitablepushability (i.e., ability to transmit force along the length of thecatheter), trackability, and flexibility, to be readily advanceablewithin the tortuous anatomy of the vasculature. Conventional ballooncatheters for intravascular procedures, such as angioplasty and stentdelivery, frequently have a relatively stiff proximal shaft section tofacilitate advancement of the catheter within the body lumen and arelatively flexible distal shaft section to facilitate passage throughtortuous anatomy, such as distal coronary and neurological arteries,without damage to the vessel wall.

Traditional catheter shafts are often constructed with inner and outermember tubing separately with an annular space therebetween for ballooninflation. In the design of catheter shafts, it is desirable topredetermine or control characteristics such as strength, stiffness andflexibility of various sections of the catheter shaft to provide thedesired catheter performance. This is conventionally performed bycombining separate lengths of tubular members of different materialand/or dimensions and then assembling the separate members into a singleshaft length. However, the transition between sections of differentstiffness or material can be a cause of undesirable kinking along thelength of the catheter. Such kinking is particularly evident in rapidexchange (RX) catheters, wherein the proximal shaft section does notinclude the additional structure of a guidewire lumen tube. For example,a conventional RX catheter generally consists of a proximal hypotubehaving a single inflation lumen therethrough and a dual lumen or coaxialtube configuration at a distal end section having both a guidewire lumenand an inflation lumen therein. Known techniques to minimize kinking atthe transition between the more rigid proximal section and the moreflexible distal section include bonding two or more segments ofdifferent flexibility together to form the shaft. Such transition bondsneed to be sufficiently strong to withstand the pulling and pushingforces on the shaft during use.

To address the described issues, catheters having varied flexibilityand/or stiffness have been developed with various sections of thecatheter shaft that are specifically tailored to provide the desiredcatheter performance. For example, each of U.S. Pat. No. 4,782,834 toMaguire and U.S. Pat. No. 5,370,655 to Burns discloses a catheter havingsections along its length which are formed from materials having adifferent stiffness; U.S. Pat. No. 4,976,690 to Solar discloses acatheter having an intermediate waist portion which provides increasedflexibility along the catheter shaft; U.S. Pat. No. 5,423,754 toCornelius discloses a catheter having a greater flexibility at itsdistal portion due to both a material and dimensional transition in theshaft; U.S. Pat. No. 5,649,909 to Cornelius discloses a catheter havinga proximal portion with greater stiffness due to the application of apolymeric coating thereto; and U.S. Publication No. 2010/0130925 toHaslinger discloses a multilayer catheter shaft using a combination of ahigh Shore D durometer value material and a lower Shore D durometervalue material to reduce kinking.

Of particular interest is the configuration and bond for the distalsegment or tip of the medical device or catheter. It is often desirableto provide the distal tip with a reduced crossing profile and generallyatraumatic or soft configuration, yet maintain sufficient strength ofthe bond between the distal tip member and the balloon and/or innertubular member to which it is attached.

Accordingly, there is a need for a catheter having a catheter shaft withan improved combination of characteristics such as strength, flexibilityand ease of manufacture. The disclosed subject matter satisfies theseand other needs.

SUMMARY OF THE DISCLOSED SUBJECT MATTER

The purpose and advantages of the disclosed subject matter will be setforth in and apparent from the description that follows, as well as willbe learned by practice of the disclosed subject matter. Additionaladvantages of the disclosed subject matter will be realized and attainedby the methods and systems particularly pointed out in the writtendescription and claims hereof, as well as from the appended drawings.

To achieve the above and other advantages and in accordance with thepurpose of the disclosed subject matter, as embodied and broadlydescribed, the disclosed subject matter includes, according to oneembodiment, a catheter comprising an elongate tubular shaft having aproximal portion and a distal portion, the elongate tubular shaftincluding an inner tubular member having a distal length extendingdistally from the distal portion of the elongate tubular shaft. Theelongate tubular shaft has an inflation lumen and a guidewire lumendefined therein, the guidewire lumen extending along at least the distallength of inner tubular member. The catheter further includes a distaltip member having a proximal end and a distal end, wherein the distaltip member is monolithic and the proximal end of the distal tip memberis secured to a distal end of the inner tubular member, the distal tipmember having a guidewire lumen in communication with the guidewirelumen of the inner tubular member. The catheter further includes aballoon having a proximal portion, a distal portion and a working lengththerebetween, the proximal portion of the balloon sealingly coupled tothe distal portion of the elongate tubular shaft. The distal portion ofthe balloon is sealingly coupled to the distal tip member and theballoon defines an inner chamber in fluid communication with theinflation lumen, wherein the proximal end of the distal tip member isdisposed within the inner chamber.

In accordance with another aspect of the disclosed subject matter, amethod of making a balloon catheter is disclosed. The method includesproviding an elongate tubular shaft having a proximal portion and adistal portion, the elongate tubular shaft including an inner tubularmember having a distal length extending distally from the distal portionof the elongate tubular shaft, the elongate tubular shaft having aninflation lumen and a guidewire lumen defined therein, the guidewirelumen extending along at least the distal length of inner tubularmember. The method further includes providing a distal tip member,wherein the distal tip member is monolithic and includes a proximal endand a distal end, the distal tip member having a guidewire lumen definedtherethrough. The distal tip member is secured to a distal end of theinner tubular member with the guidewire lumen of the distal tip memberin communication with the guidewire lumen of the inner tubular member. Aballoon is provided having a proximal portion, a distal portion and aworking length therebetween, the balloon defining an inner chambertherein. The method further includes coupling the proximal portion ofthe balloon to the distal portion of the elongate tubular shaft with theinner chamber of the balloon in fluid communication with the inflationlumen and coupling the distal portion of the balloon to the distal tipmember with the proximal end of the distal tip member disposed withinthe interior of the balloon.

In another embodiment of the disclosed subject matter, a method ofdeploying a balloon catheter is disclosed. The method includes providinga catheter comprising an elongate tubular shaft having a proximalportion and a distal portion, the elongate tubular shaft including aninner tubular member having a distal length extending distally from thedistal portion of the elongate tubular shaft. The elongate tubular shafthas an inflation lumen and a guidewire lumen defined therein, theguidewire lumen extending along at least the distal length of innertubular member. The catheter further comprises a distal tip memberhaving a proximal end and a distal end, wherein the distal tip member ismonolithic and the proximal end of the distal tip member is secured to adistal end of the inner tubular member. The distal tip member has aguidewire lumen in communication with the guidewire lumen of the innertubular member and a balloon having a proximal portion, a distal portionand a working length therebetween. The proximal portion of the balloonis sealingly coupled to the distal portion of the elongate tubularshaft, the distal portion of the balloon sealingly coupled to the distaltip member. The balloon defines an inner chamber in fluid communicationwith the inflation lumen, wherein the proximal end of the distal tipmember is disposed within the inner chamber. The method further includespositioning the balloon of the catheter within a body lumen; andinflating the balloon by introducing pressurizing fluid through theinflation lumen of the elongate tubular shaft.

It is to be understood that both the foregoing general description andthe following detailed description are embodiments and are intended toprovide further explanation of the disclosed subject matter claimed. Theaccompanying drawings, which are incorporated in and constitute part ofthis specification, are included to illustrate and provide a furtherunderstanding of the system and method of the disclosed subject matter.Together with the description, the drawings serve to explain theprinciples of the disclosed subject matter.

BRIEF DESCRIPTION OF THE DRAWINGS

The subject matter of the application will be more readily understoodfrom the following detailed description when read in conjunction withthe accompanying drawings, in which:

FIG. 1 is a schematic side view, partially in section, of a ballooncatheter embodying features of the disclosed subject matter having adistal tip member joined to an inner tubular member located within aninterior of the balloon and a single central marker band.

FIG. 2A is a schematic side view, partially in section, of a ballooncatheter embodying features of the disclosed subject matter having adistal tip member that tapers from the proximal end of the distal tipmember to the distal end of the distal tip member.

FIG. 2B is a schematic side view, partially in section, of a ballooncatheter embodying features of the disclosed subject matter having adistal tip member that tapers distal to a distal end of a balloon.

FIG. 3 is a transverse cross sectional view of the catheter of FIG. 1,taken along lines 3-3.

FIG. 4 is a transverse cross sectional view of the catheter of FIG. 1,taken along lines 4-4.

FIGS. 5A and 5B are images for purpose of comparison between schematicsof a catheter according to an embodiment of the disclosed subject matterand a conventional catheter, respectively.

FIGS. 6A and 6B are distal images of the catheter of FIGS. 5A and 5B,respectively.

FIG. 7 is a schematic side view, partially in section, of an over thewire balloon catheter embodying features of the disclosed subject matterhaving a distal tip member joined to an inner tubular member locatedwithin an interior of the balloon and two marker bands.

DETAILED DESCRIPTION

Reference will now be made in detail to embodiments of the disclosedsubject matter, an example of which is illustrated in the accompanyingdrawings. The examples are not intended to limit the scope of thedisclosed subject matter in any manner. The disclosed subject matterwill be described in conjunction with the detailed description of thesystem.

In accordance with the disclosed subject matter, a catheter is providedcomprising an elongate tubular shaft having a proximal portion and adistal portion, the elongate tubular shaft including an inner tubularmember having a distal length extending distally from the distal portionof the elongate tubular shaft. The elongate tubular shaft has aninflation lumen and a guidewire lumen defined therein, the guidewirelumen extending along at least the distal length of inner tubularmember. The catheter further includes a distal tip member having aproximal end and a distal end, wherein the distal tip member ismonolithic and the proximal end of the distal tip member is secured to adistal end of the inner tubular member, the distal tip member having aguidewire lumen in communication with the guidewire lumen of the innertubular member. The catheter further includes a balloon having aproximal portion, a distal portion and a working length therebetween,the proximal portion of the balloon sealingly coupled to the distalportion of the elongate tubular shaft. The distal portion of the balloonis sealingly coupled to the distal tip member and the balloon defines aninner chamber in fluid communication with the inflation lumen, whereinthe proximal end of the distal tip member is disposed within the innerchamber.

In accordance with another aspect of the disclosed subject matter, amethod of making a balloon catheter is disclosed. The method includesproviding an elongate tubular shaft having a proximal portion and adistal portion, the elongate tubular shaft including an inner tubularmember having a distal length extending distally from the distal portionof the elongate tubular shaft, the elongate tubular shaft having aninflation lumen and a guidewire lumen defined therein, the guidewirelumen extending along at least the distal length of inner tubularmember. The method further includes providing a distal tip member,wherein the distal tip member is monolithic and includes a proximal endand a distal end, the distal tip member having a guidewire lumen definedtherethrough. The distal tip member is secured to a distal end of theinner tubular member with the guidewire lumen of the distal tip memberin communication with the guidewire lumen of the inner tubular member. Aballoon is provided having a proximal portion, a distal portion and aworking length therebetween, the balloon defining an inner chambertherein. The method further includes coupling the proximal portion ofthe balloon to the distal portion of the elongate tubular shaft with theinner chamber of the balloon in fluid communication with the inflationlumen and coupling the distal portion of the balloon to the distal tipmember with the proximal end of the distal tip member disposed withinthe interior of the balloon.

In another embodiment of the disclosed subject matter, a method ofdeploying a balloon catheter is disclosed. The method includes providinga catheter comprising an elongate tubular shaft having a proximalportion and a distal portion, the elongate tubular shaft including aninner tubular member having a distal length extending distally from thedistal portion of the elongate tubular shaft. The elongate tubular shafthas an inflation lumen and a guidewire lumen defined therein, theguidewire lumen extending along at least the distal length of innertubular member. The catheter further comprises a distal tip memberhaving a proximal end and a distal end, wherein the distal tip member ismonolithic and the proximal end of the distal tip member is secured to adistal end of the inner tubular member. The distal tip member has aguidewire lumen in communication with the guidewire lumen of the innertubular member and a balloon having a proximal portion, a distal portionand a working length therebetween. The proximal portion of the balloonis sealingly coupled to the distal portion of the elongate tubularshaft, the distal portion of the balloon sealingly coupled to the distaltip member. The balloon defines an inner chamber in fluid communicationwith the inflation lumen, wherein the proximal end of the distal tipmember is disposed within the inner chamber. The method further includespositioning the balloon of the catheter within a body lumen; andinflating the balloon by introducing pressurizing fluid through theinflation lumen of the elongate tubular shaft.

For purpose of illustration and not limitation, reference will now bemade in detail to specific embodiments, examples of which areillustrated in the accompanying drawings. For the purposes of thisdisclosure, like reference numbers in the figures shall refer to likefeatures unless otherwise indicated. Additionally, for purpose ofunderstanding, the methods of the disclosed subject matter are describedin conjunction with the catheter and related features.

FIG. 1 illustrates a side view, partially in section, of a ballooncatheter 110 embodying features of the disclosed subject matter,generally comprising an elongate tubular shaft 111 having a proximalportion, a distal portion, an inflation lumen 112, and a guidewire lumen113 extending at least along a portion of the length of the elongatetubular shaft.

The elongate tubular shaft of the catheter can be made of a variety ofconfigurations. For example, the elongate tubular shaft can provide anover the wire (OTW) configuration with the guidewire lumen extendinggenerally across the entire length of the elongate tubular shaft. Inthis embodiment, the elongate tubular shaft can be a single piecemulti-lumen member, or can include a co-axial arrangement, as shownschematically in FIG. 1. Thus, the elongate tubular shaft can include acoaxial configuration with the inner tubular member 118 disposed withinat least a length of an outer tubular member 117 such that the outertubular member 117 and the inner tubular member 118 define the inflationlumen 112 of the elongate tubular shaft therebetween. That is, theco-axial arrangement includes outer tubular member 117 and inner tubularmember 118 with the inflation lumen 112 defined therebetween. In eitherarrangement, i.e., multi-lumen or coaxial, the inner tubular member 118extends beyond the distal end of the outer tubular member 117 andfurther defines the guidewire lumen 113, as depicted in detail in FIG.1.

As an alternative, the catheter can be a rapid exchange (RX)configuration as known in the art, with the proximal section of thecatheter comprising a proximal hypotube or the like. The distal sectionof the rapid exchange catheter can be a co-axial configuration asdescribed above or a multi-lumen configuration. In the multi-lumenconfiguration, the distal section of the catheter comprises an elongatetubular shaft includes the inflation lumen 112 extending along thelength thereof and further includes the guidewire lumen 113 extendingalong at least a portion of the length of the elongate tubular shaftmember. The inflation lumen 112 and the guidewire lumen 113 are disposedadjacent each other. The elongate tubular shaft includes an innertubular member 118 having a distal length extending distally from thedistal portion of the elongate tubular shaft and the guidewire lumenextending along at least the distal length of inner tubular member 118.Accordingly, the elongate tubular shaft can include a multi-lumenconfiguration with the inner tubular member 118 defining the guidewirelumen adjacent with the inflation lumen. For purposes of discussionherein, but not limitation, an OTW configuration is depicted in FIGS.1-7.

As embodied herein, the inner tubular member 118 can be more flexiblethan the outer tubular shaft member 117, although it is not necessaryfor the inner tubular member 118 to be more flexible than the outertubular shaft member 117. For example, in accordance with anotherembodiment, only the portion of the inner tubular member extendingdistal of the outer tubular member can have greater flexibility than theouter tubular member. Furthermore, the inner member can have a varietyof suitable configurations including being a single unitary tube, ormultiple tubes joined by end-to-end joints, butt joints, or lap joints.

In accordance with the disclosed subject matter, a distal tip member 127is depicted in FIG. 1. The distal tip member is a monolithic member andhas a proximal end 127P and a distal end 127D. The proximal end 127P ofthe distal tip member 127 is secured to a distal end 127D of the innertubular member 118. The distal tip member embodied herein has aguidewire lumen 213 defined therethrough and coupled in communicationwith the guidewire lumen 113 of the inner tubular member 118.

The distal tip member 127 can have a variety of suitable configurations.In one embodiment, as depicted in FIG. 1 for illustration, the distaltip member can have a generally cylindrical configuration with uniformdiameter and wall thickness. Alternatively, and as depicted in FIG. 2A,the distal tip member can have a distally decreasing cross-dimension,such as a taper from the proximal end of the distal tip member to thedistal end of the distal tip member. In this embodiment, the distal tipmember has a substantially constant taper from the proximal end to thedistal end.

For example, and with reference to a coronary dilatation catheter, thedistal tip member can also have a uniform or varying profile along alength of the distal tip member. The outer cross-dimension of the distaltip member can decrease in a distal direction between the proximal endand the distal end. For example, the outer cross-sectional dimension orprofile of the distal tip member at a position immediately distal of adistal end of the balloon at location L can range between approximately0.018 inches to approximately 0.028 inches. In one example, thecross-sectional profile of the distal tip member is approximately 0.023inches at the position immediately distal to the distal end of theballoon. In contrast, the distal end of the distal tip member cancomprise a cross-sectional dimension or profile at location E betweenapproximately 0.012 inches to approximately 0.028 inches. In oneexample, the cross-sectional profile of the distal tip is approximately0.017 inches at the distal end of the distal tip member for a 3.0×20 mmballoon.

In another embodiment as depicted in FIG. 2B, the distal tip member cantaper distal to a distal end of a balloon 114 at location L only. Forexample, and solely for purposes of illustration, FIG. 2B depicts adistal tip member having a uniform profile between a proximal end of thedistal tip member to the location L, and then a decreasing profiledistally therefrom. That is from the proximal end of the distal tipmember to the position L which is immediately distal to the distal endof the balloon, the distal tip member comprises a substantially uniformcross-sectional profile. However, from location L to the distal end ofthe distal tip member at location E, the distal tip member 127 tapersbeyond the distal end of the balloon. In one example with an inflatedballoon of 3.0 mm for coronary dilatation, the outer cross-sectionaldimension or profile of the distal tip member 127 at location L can beapproximately 0.021″ and the entry profile of the distal tip member 127at location E can be approximately 0.017″ for a 3×20 mm balloon. Thecrossing profile measurement of the distal tip member is taken at thedistal edge of the distal balloon seal.

The distal tip member can have a variety of suitable cross-sectionalshapes and configurations. In the embodiments of FIGS. 2A and 2B, thedistal tip member comprises a substantially circular cross-sectional,configuration. For example, and with reference to a coronary dilatationcatheter, an inner diameter of the distal tip member can range fromapproximately 0.008 inches to approximately 0.038 inches and an outerdiameter of the distal tip member can range from approximately 0.014inches to approximately 0.045 inches.

In this embodiment, the distal tip member can have a wall thickness lessthan or equal to approximately 0.006 inches. In the embodiment asdepicted in FIG. 2B, the distal tip member further includes a wallthickness that decreases in a distal direction.

Again with reference to a coronary dilatation catheter for purpose ofillustration and not limitation, the distal tip member can comprise alength of up to approximately 5 mm. In one embodiment, the distal tipmember is approximately 3 mm. The distal tip member can extend asuitable length distal to the distal end of the balloon. For example,the distal tip member extends up to approximately 2 mm distal from adistal end of the balloon.

The distal end of the distal tip member 127 can comprise a roundedconfiguration or a blunt configuration for enhanced lumen crossing. Therounded tip configuration can be formed by laser, milling or othersuitable techniques. Other embodiments of suitable tip configuration canbe used, such as those described herein are also described in U.S.application Ser. No. 11/958,106; U.S. Pat. No. 7,862,541; U.S.application Ser. No. 12/983,504; U.S. Pat. No. 7,549,975; U.S. patentapplication Ser. No. 12/468,745; U.S. Pat. No. 6,964,750; and U.S.patent application Ser. No. 11/241,936, the contents of which are hereinincorporated by reference in their entirety.

The distal tip member can be coupled to the elongate tubular shaft in aplurality of suitable ways. For purposes of example, the distal tipmember can be coupled to the inner tubular member by a butt joint 126 orby a lap joint 128 as shown with respect to FIGS. 2A and 2B,respectively. Other suitable junctures and joints likewise can be used.As depicted in FIG. 2B, the distal tip member and the inner tubularmember are coextensive with each other. The distal tip member isgenerally configured to provide flexibility and is typically formed of asofter polymeric material than the adjacent section of the inner tubularmember. In this manner, the softer distal tip member can be overlappedwith the outer surface of the inner tubular member and bonded thereto orthe distal tip member can overlap the outer surface of the inner tubularmember and bonded thereto.

The distal tip member can include a plurality of suitable materials. Forexample, the distal tip member can be formed of a variety of suitablepolymeric materials. For example, it can be desirable for the surface ofthe tip member to be compatible for fusion or thermal bonding with thematerial of the balloon and/or inner tubular member, as furtherdiscussed here. In one embodiment, the distal tip member is made ofpolyether block amide (PEBAX) or block copolymer or a thermoplastic. Therelatively low Shore durometer hardness of the soft distal tip materialcan range from about 55D to 72D. In one embodiment, the distal tipmember is formed at least in part of a softer polymeric material than adistal end portion of the inner tubular member immediately proximallyadjacent to the distal tip member. The distal tip member is softer andmore flexible than the inner tubular member as a whole. In this manner,the distal tip member 127 can be formed of a relatively soft polymericmaterial to provide an atraumatic distal leading end for the catheter.

In some embodiments, the distal tip member is a single layer tubularmember, such as a polymer capable of fusion bond with an adjacent layerof the inner tubular member 118 and/or the balloon. Alternatively, amultilayer configuration can be used with the exposed layers compatiblefor fusion or thermal bonding with the material to be joined, e.g., theinner tubular member and/or the balloon. If the material of the distaltip member is not compatible for fusion or thermal bonding, then otherconventional bonding or joining techniques can be used, such asadhesives or the like.

The distal tip member 127 provides for a flexible, ultra low profile forsuperb deliverability. The low crossing profile allows for easier accessto complex lesions. In this manner, the catheter can be advanced withina vasculature to position the balloon at a desired location.

The catheter according to embodiments of the disclosed subject mattercan also include a coating, such as a hydrophilic coating. For example,in one embodiment, at least an exterior of the distal tip memberincludes a coating. Such hydrophilic coatings are described in U.S.Publication 2010/0285085 and U.S. Publication 2010/0189876, the contentsof which are herein incorporated by reference in their entirety.

As discussed above, the catheter further includes a balloon having adeflated condition and an inflated condition. The balloon generallyincludes a proximal portion, a distal portion and a working lengththerebetween. The proximal portion of the balloon is sealingly coupledto the distal portion of the elongate tubular shaft and the distalportion of the balloon is sealingly coupled to the distal tip membersuch that the proximal end of the distal tip member is disposed withinthe inner chamber. The balloon defines an inner chamber in fluidcommunication with the inflation lumen.

For example, and with reference to FIG. 1, the proximal balloon 114includes a proximal skirt section 116 p, a proximal cone section 115 p,a distal cone section 115 d, and a distal skirt section 116 d. Theballoon 114 includes a working length between the proximal cone section115 p and the distal cone section 115 d. As illustrated herein, theproximal skirt section is sealingly secured to the elongate tubularshaft member. In the embodiment of FIG. 1, the proximal skirt section116 p is coupled to the outer tubular member 117. The distal skirtsection 116 d is sealingly secured to the distal tip member 127. Theinner chamber 141 of the balloon is defined between the proximal skirtsection 116 p and the distal skirt section 116 d of the balloon. Theinner chamber is coupled to the elongate tubular shaft in fluidcommunication with the inflation lumen 112. As illustrated in FIG. 1,the proximal end 127P of the distal tip member within the inner chamberis coupled with the inner tubular member 118. Accordingly, the distalskirt section 116 d is disposed distal to the proximal end 127P of thedistal tip member 127.

FIG. 3 is a cross-section of the catheter 110 of FIG. 1 along the lines3-3. In FIG. 3, the distal tip member 127 defines the guidewire lumen213 with the guidewire 120 extending therethrough. The balloon 114 is inan inflated condition and the distal cone 115 d extends radiallyoutwardly from the distal tip member 127.

FIG. 4 is a cross-section of the catheter 110 of FIG. 1 along the lines4-4. In FIG. 4, the distal skirt section 116 d is sealingly secured tothe distal tip member 127. The distal tip member 127 further defines theguidewire lumen 213 with the guidewire 120 extending therethrough.

The proximal end 127P of the distal tip member can be disposed at asuitable location within the inner chamber of the balloon, as desired.For example, in one embodiment, the proximal end 127P can be locatedproximate to the distal skirt section 116 d such as for a stent deliverysystem or the like. In another embodiment, the proximal end 127P isspaced proximally from the distal end of the balloon, as shown in FIG.2A and FIG. 2B, such as for a dilatation balloon catheter. Generally,the joint or juncture between the inner tubular member and the proximalend of the distal tip member is located at or distal to the center ofthe balloon interior. The location of the proximal end 127P within theballoon 114 allows for a smoother gradual transition for the catheter110, as compared with conventional catheters.

FIG. 5A depicts a catheter according to an embodiment of the disclosedsubject matter whereas FIG. 5B depicts a known catheter. In FIG. 5A, thecatheter includes a gradual transition between a distal end portion ofthe inner tubular member 118 and the proximal end portion of the distaltip member 127. FIG. 5A depicts the inner tubular member 118 coupled tothe distal tip member 127 within the inner chamber of the balloon 114with a guidewire 120 disposed therethough. A radiopaque marker 140 isdisposed on the tip member 127. The distal skirt section 116 d of theballoon is disposed on the distal tip member distal to the proximal endof the distal tip member 127. This gradual transition is accomplished byone or more of the coextensive length of the inner tubular member andthe distal tip member, the location of the juncture within the innerchamber of the balloon, the tapered shape of the distal tip member, theuse of a softer material of the distal tip member than the inner tubularmember, and/or an increased length of the distal tip member. Incontrast, FIG. 5B shows an abrupt shift of an inner member to a tip.Such known configuration promotes stiffness at the distal portion of thecatheter and kinking of the catheter when moving through tortuous paths.

FIGS. 6A and 6B depict distal views the catheters of FIGS. 5A and 5B,respectively, with reference to the catheter in accordance with thedisclosed subject matter herein. In FIG. 6A, the junction of the innertubular member 118 to the distal tip member 127 is disposed within theinner chamber of the balloon 114 and spaced proximally from the junctionof the distal tip member 127 to the distal portion of the balloon 114 atthe distal skirt section 116 d. This proximal spacing allows for agradual transition of the catheter to enhance flexibility and preventkinking. A radiopaque marker 140 is disposed on the distal tip member127 in FIG. 6A. By contrast, and with reference to a conventionalcatheter as shown in FIG. 6B, the junction of the inner member to thetip is located at the junction of the distal end of the balloon to theinner member. Such configuration as depicted in FIGS. 5B and 6B createsan abrupt and less flexible transition.

As further depicted in FIGS. 1 and 7, and in accordance with anotheraspect of the disclosed subject matter, the catheter can include atleast one radiopaque marker. The radiopaque marker can be coupled to theinner tubular member. The marker can be made of radiopaque material,such as metal or a radiopaque loaded polymer such as disclosed in U.S.Ser. No. 11/455,382, which is incorporated herein by reference in itsentirety.

The location of the markers can depend on the size of the balloon. Forexample, in embodiments having smaller balloons, one radiopaque markercan be used as depicted in FIG. 1. In embodiments where one radiopaquemarker is used, the marker can be located in the center of theinflatable working length 114 w. However, radiopaque markers can beprovided at a variety of locations including at the ends of the workinglength section depending on the size of the balloon.

FIG. 7 depicts another arrangement of the at least one marker coupled tothe inner tubular member of the catheter. The catheter 110 has tworadiopaque markers 140 located on the inner tubular member 118 withinthe inner chamber 141 of the balloon 114 and along the working length114 w of the balloon 114. In this embodiment, the markers 140 aregenerally aligned with the proximal and distal cone sections 114 c todefine the working length 114 w of the balloon therebetween.

Further embodiments of catheters having marker configurations aredescribed in U.S. application Ser. No. 11/775,480; U.S. application Ser.No. 12/945,566; U.S. Pat. No. 7,862,541; application Ser. No.12/983,504; U.S. Pat. No. 7,549,975; U.S. patent application Ser. No.12/468,745; U.S. Pat. No. 6,964,750; U.S. application Ser. No.11/455,382; U.S. Pat. Nos. 7,833,597; 7,322,959; 7,303,798; U.S.application Ser. No. 11/775,480; U.S. application Ser. No. 12/945,566;U.S. Publication 2010/0285085; U.S. Publication 2010/0189876; and U.S.patent application Ser. No. 11/241,936; the contents of which are hereinincorporated by reference in their entirety.

The catheter can further includes a medical device is coupled to theballoon. An example of a medical device includes stents and othersuitable devices and implants likewise delivered using the catheter andmethod. For details of example stents, see for example, U.S. Pat. No.5,507,768 (Lau, et al.) and U.S. Pat. No. 5,458,615 (Klemm, et al.),which are incorporated herein by reference.

The elongate tubular shaft member including the outer tubular member andthe inner tubular member can have a multilayered configuration with alayer of material readily bondable. For example, the inner tubularmember can have an outer layer of a material such as a polyamide whichfacilitates bonding to adjacent components, and an inner layer of alubricious/low friction material such as HDPE.

In another embodiment, the inner tubular member is a trilayer tubularmember having an inner layer typically formed of a lubricous materialsuch as HDPE, a middle tie layer such as a functionalized polyolefinadhesive polymer, and an outer readily bondable layer such as apolyamide such as a nylon or a polyether block amide (PEBAX).

In the embodiment as depicted in FIG. 1, the balloon 114 is depicted asa single layer balloon. However, multilayered balloons are contemplatedherein. An example of a multilayered balloon for a catheter is describedin U.S. Pat. No. 7,828,766 and U.S. application Ser. No. 12/897,202, thecontents of which are herein incorporated by reference in theirentirety. Further, various embodiments of catheters with other balloonconfigurations are described in U.S. Pat. No. 6,923,822; U.S.application Ser. No. 11/189,536; U.S. Publication Nos. 2009/0036829 and2007/0021772, the contents of which are herein incorporated by referencein their entirety.

The dimensions of catheters of the disclosed subject matter aredetermined largely by the size of the balloon and guidewire to beemployed, the catheter type, and the size of the artery or other bodylumen through which the catheter must pass, or the size of the stentbeing delivered. For example, the outer tubular member 117 can have anouter diameter of about 0.025 to about 0.04 inch (0.064 to 0.10 cm), insome embodiments about 0.037 inch (0.094 cm), and the wall thickness ofthe outer tubular member 117 can vary from about 0.002 to about 0.008inch (0.0051 to 0.02 cm), in some embodiments about 0.003 to 0.005 inch(0.0076 to 0.013 cm). The inner tubular member 118 typically has aninner diameter of about 0.01 to about 0.018 inch (0.025 to 0.046 cm), insome embodiments about 0.016 inch (0.04 cm), and a wall thickness ofabout 0.004 to about 0.008 inch (0.01 to 0.02 cm). The overall length ofthe catheter 110 may range from about 100 to about 150 cm, and in someembodiments about 143 cm. The balloon 114 can have a length about 0.8 cmto about 6 cm (0.315 inches to 2.362 inches), and an inflated workingdiameter of about 0.5 to about 10 mm (0.0197 to 0.3937 inches). Thedistal tip member 127 can range from 1 mm to 35 mm in length and aninner diameter of about 0.010 to about 0.035 inch (0.025 to 0.046 cm),in some embodiments about 0.016 inch (0.04 cm), and a wall thickness ofabout 0.004 to about 0.008 inch (0.01 to 0.02 cm). Other dimensions areherein contemplated and the above dimensions are provided as examplesonly.

Although the tubular members of the elongate tubular shafts 111 areillustrated as having uniform inner and outer diameters and wallthicknesses, each or both of these members can be provided with taperinginner and/or outer diameters at various locations along the length ofthe elongate tubular shaft. The inner tubular member 118 can be providedwith a tapered distal end (i.e., which decreases the outer diameter ofthe tubular member by tapering uniformly around the entire circumferenceof the tubular member), and the proximal end of the soft tip member canoverlap the tapered distal end for bonding thereto. Furthermore and forexample, the tip member 127 can have a thinner wall thickness than theend section of the inner tubular member to be bonded thereto, in whichcase the inner surfaces can be aligned and the outer surface of theinner member is caused to flow distally during bonding to smooth theouter surface at the junction.

In accordance with another aspect of the disclosed subject matter, amethod of making a balloon catheter is disclosed. The method includesproviding an elongate tubular shaft having a proximal portion and adistal portion, the elongate tubular shaft including an inner tubularmember having a distal length extending distally from the distal portionof the elongate tubular shaft, the elongate tubular shaft having aninflation lumen and a guidewire lumen defined therein, the guidewirelumen extending along at least the distal length of inner tubularmember. The method further includes providing a distal tip member,wherein the distal tip member is monolithic and includes a proximal endand a distal end, the distal tip member having a guidewire lumen definedtherethrough. The distal tip member is secured to a distal end of theinner tubular member with the guidewire lumen of the distal tip memberin communication with the guidewire lumen of the inner tubular member. Aballoon is provided having a proximal portion, a distal portion and aworking length therebetween, the balloon defining an inner chambertherein. The method further includes coupling the proximal portion ofthe balloon to the distal portion of the elongate tubular shaft with theinner chamber of the balloon in fluid communication with the inflationlumen and coupling the distal portion of the balloon to the distal tipmember with the proximal end of the distal tip member disposed withinthe interior of the balloon.

A variety of techniques can be used to couple or otherwise form thejunction or junctures of the catheter disclosed herein. For example,reference is made to the juncture between the balloon and the distal tipmember. To couple the distal portion of the balloon to the distal tipmember, a shrink wrap can be provided over at least a portion of thedistal portion of the balloon and the distal tip member. At least theportion of the distal portion of the balloon is thermally bonded to thedistal tip member using a laser or the like. For example, the laser canbe passed in a helical manner relative the outer surface of the distaltip member along the longitudinal axis thereof. In this manner, thematerial of the distal portion of the balloon and of the distal tipmember will soften and melt. As the laser is moved distally, in ahelical fashion about the longitudinal axis of the tip member, thesofter and/or molten material will be urged in a distal direction toform a tapered shape beneath the shrink wrap. Once completed, the shrinkwrap can be removed. The distal end of the distal tip member can berounded or otherwise shaped to form a less traumatic end using a laser,milling or other process.

Likewise, when bonding the proximal end of the distal tip member to theinner tubular member, a mandrel can be provided inside the tubularmembers 118, 127 to support the luminal shape. Heat shrink tube (notshown) or the like can be provided on the tubular members 118, 127 atthe location of the mating or coupled surfaces, to facilitate a smoothtransition along the juncture during bonding. The shrink tube andmandrel are removed after formation of the bond.

The elongate tubular shaft outer and inner tubular members and tipmember can be formed by conventional techniques, for example byextruding and necking materials already found useful in intravascularcatheters such a polyethylene, polyvinyl chloride, polyesters,polyamides, polyimides, polyurethanes, and composite materials. Thevarious components may be joined using conventional bonding methods suchas, but not limited to, by fusion bonding or use of adhesives. The innertubular member and outer tubular member can be multilayered tubing, orsections of tubing joined end-to-end, as is conventionally known forballoon catheter shafts. Although the elongate tubular shaft isillustrated as having an inner and outer tubular member, a variety ofsuitable shaft configurations can be used including a multi-lumenextruded shaft having a side-by-side lumens extruded therein. For rapidexchange configurations, the outer tubular member can further includesupporting members including a high strength member such as a hypotubein the proximal shaft section and/or across the guidewire proximal portin the rapid exchange embodiment (not shown). Example configurations aredisclosed in U.S. Pat. No. 7,906,066, the subject matter of which isincorporated herein by reference in its entirety.

During manufacture, the balloon can be formed using conventionaltechniques and bonded to the distal tip member by at least one of laserbond or heat fusion. The distal cone of the balloon can be cooled duringheat fusion bonding of the distal skirt section of the balloon to theunderlying section of the distal tip member, for example by directing acooling fluid (e.g., air stream) at the distal cone. Prior to bonding,the distal skirt section 116 of the balloon can have an inner diameterclosely matched to the outer diameter of the distal tip member, thedistal tip member 127, such that the resulting distal skirt section sealhas a low profile. During assembly, the distal tip member 127 isdisposed within the distal skirt section 116 d. With the distal tipmember 127 thus in position under the distal skirt 116 d, the bondbetween the distal skirt 116 d and distal tip 127 is formed as describedherein. Various embodiments of catheters with other balloonconfigurations are described in U.S. Pat. No. 6,923,822; U.S.application Ser. No. 11/189,536; U.S. Publication Nos. 2009/0036829 and2007/0021772, the contents of which are herein incorporated by referencein their entirety. An example of a multilayered balloon for a catheteris described in U.S. Pat. No. 7,828,766 and U.S. application Ser. No.12/897,202, the contents of which are herein incorporated by referencein their entirety.

In another embodiment of the disclosed subject matter, a method ofdeploying a balloon catheter is disclosed. The method includes providinga catheter comprising an elongate tubular shaft having a proximalportion and a distal portion, the elongate tubular shaft including aninner tubular member having a distal length extending distally from thedistal portion of the elongate tubular shaft. The elongate tubular shafthas an inflation lumen and a guidewire lumen defined therein, theguidewire lumen extending along at least the distal length of innertubular member. The catheter further comprises a distal tip memberhaving a proximal end and a distal end, wherein the distal tip member ismonolithic and the proximal end of the distal tip member is secured to adistal end of the inner tubular member. The distal tip member has aguidewire lumen in communication with the guidewire lumen of the innertubular member and a balloon having a proximal portion, a distal portionand a working length therebetween. The proximal portion of the balloonis sealingly coupled to the distal portion of the elongate tubularshaft, the distal portion of the balloon sealingly coupled to the distaltip member. The balloon defines an inner chamber in fluid communicationwith the inflation lumen, wherein the proximal end of the distal tipmember is disposed within the inner chamber. The method further includespositioning the balloon of the catheter within a body lumen; andinflating the balloon by introducing pressurizing fluid through theinflation lumen of the elongate tubular shaft.

While the present disclosed subject matter is described herein in termsof certain embodiments, those skilled in the art will recognize thatvarious modifications and improvements may be made to the disclosedsubject matter without departing from the scope thereof. Moreover,although individual features of one embodiment of the disclosed subjectmatter may be discussed herein or shown in the drawings of the oneembodiment and not in other embodiments, it should be apparent thatindividual features of one embodiment may be combined with one or morefeatures of another embodiment or features from a plurality ofembodiments.

It will be understood that the above description of the presentdisclosed subject matter is susceptible to various modifications,changes and adaptations, and the same are intended to be comprehendedwithin the meaning and range of equivalents of the appended claims.

What is claimed is:
 1. A catheter comprising: an elongate tubular shafthaving a proximal portion and a distal portion, the elongate tubularshaft including an inner tubular member having a distal length extendingdistally from the distal portion of the elongate tubular shaft, theelongate tubular shaft having an inflation lumen and a guidewire lumendefined therein, the guidewire lumen extending along at least the distallength of the inner tubular member; a distal tip member having aproximal end and a distal end, wherein the distal tip member ismonolithic and the proximal end of the distal tip member is secured to adistal end of the inner tubular member, the distal tip member having aguidewire lumen in communication with the guidewire lumen of the innertubular member; and a balloon having a proximal cone section, a distalcone section and a working length between the proximal cone section andthe distal cone section, a proximal portion of the balloon sealinglycoupled to the distal portion of the elongate tubular shaft and a distalportion of the balloon sealingly coupled to the distal tip member, theballoon defining an inner chamber in fluid communication with theinflation lumen; wherein the proximal end of the distal tip member isdisposed within the inner chamber along the working length of theballoon, and further wherein the distal tip member tapers an entirelength from the proximal end of the distal tip member to the distal endof the distal tip member.
 2. The catheter according to claim 1, whereinan outer cross-dimension of the distal tip member decreases in a distaldirection between the proximal end and the distal end.
 3. The catheteraccording to claim 1, wherein the distal tip member has a substantiallyconstant taper from the proximal end to the distal end.
 4. The catheteraccording to claim 1, wherein the distal tip member has an outercross-dimension at a position immediately distal to a distal end of theballoon between approximately 0.018 inches to approximately 0.028 inchesand the distal end of the distal tip member comprises an outercross-dimension of between approximately 0.012 inches to approximately0.022 inches.
 5. The catheter according to claim 1, wherein the distaltip member has an inner diameter between 0.010 inches to approximately0.035 inches.
 6. The catheter according to claim 1, wherein the distaltip member has a wall thickness less than or equal to approximately0.006 inches.
 7. The catheter according to claim 1, wherein the distaltip member has a length of up to approximately 5 mm.
 8. The catheteraccording to claim 1, wherein the distal tip member extendsapproximately 2 mm distal to the distal end of the balloon.
 9. Thecatheter according to claim 1, wherein the distal end of the distal tipmember comprises at least one of a rounded configuration or a bluntconfiguration.
 10. The balloon catheter according to claim 1, whereinthe distal tip member and the inner tubular member are coupled by atleast one of a lap-joint or a butt-joint.
 11. The catheter according toclaim 1, wherein the distal tip member includes a material having aShore durometer hardness between approximately 55D to approximately 72D.12. The catheter according to claim 1, wherein the distal tip memberincludes at least one of a block copolymer or a thermoplastic.
 13. Thecatheter according to claim 1, wherein an exterior of the distal tipmember includes a coating.
 14. The catheter according to claim 1,wherein the balloon is bonded to the distal tip member by at least oneof laser bond or heat fusion.
 15. The catheter according to claim 1,further comprising at least one radiopaque marker coupled to the innertubular member.
 16. The catheter according to claim 1, furthercomprising a medical device coupled to the balloon.
 17. The catheteraccording to claim 1, wherein the elongate tubular shaft includes acoaxial configuration with the inner tubular member disposed within atleast a length of an outer tubular member, the outer tubular member andthe inner tubular member defining the inflation lumen of the elongatetubular shaft therebetween.
 18. The catheter according to claim 1,wherein the elongate tubular shaft includes a multi-lumen configurationwith the inner tubular member defining the guidewire lumen adjacent withthe inflation lumen.
 19. The catheter according to claim 1, wherein theproximal end of the distal tip member is located at or distal to acenter of the inner chamber.
 20. A method of making a balloon catheter,comprising: providing an elongate tubular shaft having a proximalportion and a distal portion, the elongate tubular shaft including aninner tubular member having a distal length extending distally from thedistal portion of the elongate tubular shaft, the elongate tubular shafthaving an inflation lumen and a guidewire lumen defined therein, theguidewire lumen extending along at least the distal length of innertubular member; providing a distal tip member, wherein the distal tipmember is monolithic and includes a proximal end and a distal end, thedistal tip member having a guidewire lumen defined therethrough;securing the distal tip member to a distal end of the inner tubularmember with the guidewire lumen of the distal tip member incommunication with the guidewire lumen of the inner tubular member;providing a balloon having a proximal cone section, a distal conesection and a working length between the proximal cone section and thedistal cone section, the balloon defining an inner chamber therein;coupling the proximal portion of the balloon to the distal portion ofthe elongate tubular shaft with the inner chamber of the balloon influid communication with the inflation lumen; and coupling the distalportion of the balloon to the distal tip member with the proximal end ofthe distal tip member disposed within the inner chamber along theworking length of the balloon, and further wherein the distal tip membertapers an entire length from the proximal end of the distal tip memberto the distal end of the distal tip member.
 21. The method of claim 20,wherein the coupling the distal portion of the balloon to the distal tipmember includes providing a shrink wrap over at least a portion of thedistal portion of the balloon and the distal tip member; thermallybonding at least the portion of the distal portion of the balloon to thedistal tip member; and removing the shrink wrap.
 22. The method of claim20, further comprising rounding the distal end of the distal tip member.